feat: complete CMS v2 with Docker, Fischerei, Meetings, Verband modules + UX audit fixes

Major changes:
- Docker Compose: full Supabase stack (11 services) equivalent to supabase CLI
- Fischerei module: 16 DB tables, waters/species/stocking/catch books/competitions
- Sitzungsprotokolle module: meeting protocols, agenda items, task tracking
- Verbandsverwaltung module: federation management, member clubs, contacts, fees
- Per-account module activation via Modules page toggle
- Site Builder: live CMS data in Puck blocks (courses, events, membership registration)
- Public registration APIs: course signup, event registration, membership application
- Document generation: PDF member cards, Excel reports, HTML labels
- Landing page: real Com.BISS content (no filler text)
- UX audit fixes: AccountNotFound component, shared status badges, confirm dialog,
  pagination, duplicate heading removal, emoji→badge replacement, a11y fixes
- QA: healthcheck fix, API auth fix, enum mismatch fix, password required attribute

apps/web/app/api/club/course-register/route.ts

@@ -0,0 +1,52 @@
+import { NextResponse } from 'next/server';
+
+import { getSupabaseServerAdminClient } from '@kit/supabase/server-admin-client';
+
+export async function POST(request: Request) {
+  try {
+    const body = await request.json();
+    const { courseId, firstName, lastName, email, phone } = body;
+
+    if (!courseId || !firstName || !lastName || !email) {
+      return NextResponse.json(
+        { error: 'Kurs-ID, Vorname, Nachname und E-Mail sind erforderlich' },
+        { status: 400 },
+      );
+    }
+
+    if (!/^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email)) {
+      return NextResponse.json(
+        { error: 'Ungültige E-Mail-Adresse' },
+        { status: 400 },
+      );
+    }
+
+    const supabase = getSupabaseServerAdminClient();
+
+    const { error } = await supabase.from('course_participants').insert({
+      course_id: courseId,
+      first_name: firstName,
+      last_name: lastName,
+      email,
+      phone: phone || null,
+      status: 'enrolled',
+      enrolled_at: new Date().toISOString(),
+    });
+
+    if (error) {
+      console.error('[course-register] Insert error:', error.message);
+      return NextResponse.json(
+        { error: 'Anmeldung fehlgeschlagen' },
+        { status: 500 },
+      );
+    }
+
+    return NextResponse.json({
+      success: true,
+      message: 'Anmeldung erfolgreich',
+    });
+  } catch (err) {
+    console.error('[course-register] Error:', err);
+    return NextResponse.json({ error: 'Serverfehler' }, { status: 500 });
+  }
+}